I seriously think I'm Bipolar Type II. Do you have it?

I'm on the "depression" side of the cycle again. Usually it lasts about three weeks, and comes in short bursts of extreme torpor (like revving a car on park--no matter how much I rev the car, it doesn't go anywhere), and just a general state of relative lowness. The "manic" stages aren't that intense, but usually I'm unrealistically optimistic. This continues sinusoidally with a period of six weeks--three weeks depression, three weeks mania, and there's a greater variation in intensity over a period of three months--three months more generally happy, and three months more generally down (thinking of Fourier transforms now). Ugh, I'm not sure whether the intense lows are a product of my ADHD medication (I think it's Concerta), or if it's a product of this bipolarism. Either way, I feel so bleh lately... x.x